Manufacture of cellulose esters



UNITED STATES PATENT OFFICE.

SOGIETE CHIMIQUE DES USINES DU RHONE MONN ET ET CARTIER), OF PARIS, FRANCE.

(ANCIENNEMENT GILLIARD I.

v MANUFACTURE OF CELLULOSE ESTERS.

No Drawing.

To all whom it may concern Be it known that we. Josnrn Kon'rsonn'r, of 67 Boulevard des Belges, Lyon, France, a citizen of the Confederatlon of Switzerland. and MAURICE BEUDET, of 25 Rue Bueaud, Lyon, France, a citizen of the French .iepublic, chemists, have invented certain new and useful Improvements in or Relating to the Manufacture of Cellulose Esters, (for which I have filed ap lications in France, June 20, 1919, and in reat Britain, June 3, 1920,) of which the following is a specification. I

In a previous specification, Patent No. 1258913, one of the present inventors has described a method of preparation of cellulose acetates consisting in converting the cellulose into a fluid mass by a preliminary treatment with glacial acetic acid containing from 1 to 20% acetic anhydrid in presence of a condensing agent, acetylating the product with a further quantity of acetylating agent, and precipitating the acetyl produced after or Without a partial saponification.

In the above specification only one example is quoted in which the temperature at which the reaction is caused to take place is 30 C. and the quantity of sulfuric acid used is 5% of the cellulose to be acetylated. In proceedin according to this example an acetate of cel ulose is obtained which has the following properties: It is insoluble in nitrobenzene, acetone and ether, ver little soluble in alcohol and easily soluble 1n chloreform.

The process described in this specification No. 1,258,913 is susceptible of very wide application; we have discovered that by varying the strength of acid and that by varying the proportions and the temperature at which the reaction is caused to take place the process yields products the properties of which are very different to those lndicated in the only example quoted. I

The present invention relates to a variation of the example quoted in the specification No. 1,258,913 by means of which very different products are obtained, and notably products which are insoluble in chloroform. The variation consists in attenuating the preliminary treatment described in the above mentioned specification. This attenuation may be obtained in two ways; either the temperature may be reduced below the tem- Specification of Letters Patent.

Patented Aug. 30, 1921.

Application filed January 12, 1921. Serial No. 436,795.

perature mentioned in the example, that is below 30 (1., to a variable extent, possibly down to 0 C. or else the proportion, of sulfuric acid to the cellulose used may be de creased below the proportion mentioned in the example, that isit may be reduced below 5%. It is understood that both methods may be used simultaneously, and that the temperature may be reduced together with a dlminution in the quantity of sulfuric acid. c

The following examples gii e products having diflerent properties than those of the efiample given in the specification'quoted a ove.

Example I 100 parts of cellulose are maintained in contact for 3 to 4 hours at 25 C. with a mixture constituted as follows Acetic acid 100%, 610 parts. 7

Sulfuric acid 100%, 5 parts.

Acetic anhydrid, 50 parts.

The cellulose disintegrates rapidly and soon constitutes ahomogeneous paste very easily stirred.

One adds then, 250 parts of acetic anhydrid. By maintaining .the temperature at about 40 C. one obtains, after from 1 to 2 hours, a perfectly clear viscous mass which, precipitated in water gives a cellulose acetate which is insoluble in chloroform but which becomes translucent in it and swells' I considerably.

Example H.

Ee'mple III.

610 parts acetic acid 100% 3 parts sulfuric acid 100% and 50 parts acetic anhydrid are added to 100 parts of cellulose.

The mixture is heated at 29 C. for about 4 hours. At the end of this time the reacting mass presents the appearance of a mash which can easily be triturated and which lends itself perfectly to acetylation.

Exam- This acetylation is performed in condi Example IV.

The acetate obtained as describedin Example III, when partly saponified, leads to the production of new acetates, some of which are insoluble in chloroform and soluble in acetone.

-These examples may of course be varied between wide limits, with respect to the quantity of condensing agent, and the temperature at which the preliminary treatment takes place, provided that the variations are such as to attenuate the said treatment.

What we claim and desire to secure by Letters Patent is 1. In the prmess of the manufacture o cellulose acetate in which the cellulose is converted into a fluid mass by subjecting it t0 a preliminary treatment with glacial acetic acid containing 1 to 20 er cent. of acetic anhydrid and sulfuric acid as a con- (lensing agent, maintaining the temperature above 0 C. and below 30 C. during the preliminary process, whereby the product of the acetylation obtained is insoluble in chloroform.

2. Inthe process of the manufacture of cellulose acetate in which the cellulose is converted into a fluid mass by subjecting it to a preliminary treatment with glacial acetic acid containing l'to 20 or cent. of acetic anhydrid and sulfuric acid as a con- (lensing agent, maintaining the temperature above 0 C. and below 30 C. during the preliminary process, the proportion of sulfuric acid. to the cellulose used. being less than 5 per cent., whereby the product of the acetylation obtained is insoluble in chloroform. 1

3. The preliminary treatment of the proc- --ess of manufacture of a cellulose acetate insoluble in chloroform consisting in maintaining at 25 C. for 3 to 4 hours a mixture of 100 parts of" cellulose, 610 parts of acetic acid 100%, 5 parts of sulfuric acid 100%, parts of acetic anhydrid.

l. The new products obtained by the process claimed in claim 1, being acetates of cellulose insoluble in chloroform.

' In testimony whereof we have signed our names to this specification.

' JOSEPH KOETSCHET MAURICE BEUDET. Witnesses:

CYRUS B. FOLLMER, -LUCIENNE BOUVERET. 

